Removable inks can be used in a variety of printing applications. There is a particular need for removable inks for printing on plastic substrates. For example, it can be desirable to print information on plastic ophthalmic lenses using a removable ink. Unfortunately, some existing removable inks have low adhesion to plastic substrates and/or must be removed from the substrate using an organic solvent. In addition, some previous removable inks cannot be reliably printed using ink jet printers. Instead, such inks can clog the ink jet print head of an ink jet printer, resulting in excessive maintenance, repair, and/or replacement of ink jet print heads. Moreover, some existing inks do not provide sufficient color contrast on a variety of plastic substrates, including transparent substrates that may be light or dark in tint.
Therefore, there exists a need for improved compositions for printing applications, including compositions that can be removed from plastic substrates in a more facile manner while also providing sufficient adhesion to a plastic substrate to resist removal of the ink during handling of the substrate.